我试图从一个由servlet设置和调度的jsp页面访问会话属性,但是我收到错误消息"jsp:attribute必须是标准或自定义操作的子元素".可能有什么问题,我是否错误地访问了它？以下是代码段.
Servlet的:
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
HttpSession session = request.getSession();
session.setAttribute("Questions", getQuestion());
System.out.println(session.getAttribute("Questions"));
RequestDispatcher req = request.getRequestDispatcher("DisplayQuestions.jsp");
req.forward(request, response);
}
private QuestionBookDAO getQuestion(){
QuestionBookDAO q = new QuestionBookDAO();
q.setQuestion("First Question");
q.setQuestionPaperID(100210);
q.setSubTopic("Java");
q.setTopic("Threads");
return q;
}
我能够成功设置会话属性.但是当我尝试在我的jsp文件(下面)中访问它时,我收到运行时错误
<jsp:useBean id="Questions" type="com.cet.evaluation.QuestionBook" scope="session">
<jsp:getProperty property="Questions" name="questionPaperID"/>
<jsp:getProperty property="Questions" name="question"/>
</jsp:useBean>
bean QuestionBook包含两个私有变量questionPaperID和问题 我在Tomcat上运行应用程序,下面是抛出的错误.
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception …我试图只迭代我的Map中的第一个"n"值,是否有任何方法可用或我只需要使用count变量控制它.
下面是一个例子,我已经排序了一组属于同一个城市的名字.现在我只想要前10个城市和人名.
for (Map.Entry<String, List<String>> entry : map.entrySet()) {
List<String> list = entry.getValue();
// Display list of people in City
}
是否有可以保存固定数量的键值对的Map实现？请指点一下.
谢谢,
-Vijay Selvaraj